The long range goal of this proposal is to test the hypothesis that regulatory elements derived from Mup-1.5a/5b, the submandibular gland- specific isotype of mouse major urinary protein gene (MUP), can direct the expression of biologically active peptides to the submandibular gland. There is a tremendous interest in finding methods to stimulate mucosal immunity, both to combat infections, and to develop vaccines effective at the mucosal surfaces. in all the mucosal secretions, the predominant immunoglobulin is IgA. A major goal of this proposal is to test the hypothesis that salivary gland IgA responses can be enhanced in vivo by targeting the expression of specific cytokines specifically to the epithelial cells of the submandibular gland. We identified a submandibular gland-specific enhancer/promoter in Mup- 1.5a/5b. Transgenic lines will be generated by introducing recombinant expression plasmids containing human and murine IL-6 cDNA controlled by Mud 1.5a/5b regulatory elements into mouse embryos. in the transgenic lines, the tissue- and cell type- specificity of transcription and the mode of secretion of transgene-encoded IL-6 will be determined by Northern analyses, and histochemical and immunological methods. IgA responses will be assessed in the salivary glands of mice expressing transgene-encoded IL-6, and as a control, in other mucosal tissues, e.g. the lamina propria of the small intestine and the lungs, in non-immunized mice and in mice immunized with Porhyromonas gingivalis 381 fimbriae. Histochemical methods will be used to determine whether enhanced submandibular gland levels of IL-6 bring about oral inflammation, autoimmune responses, or cell proliferation. Northern analysis will be used to detect the potential induction of acute-phase response genes in the liver. With the view of regulating the expression of transgene-encoded cytokines, minimal regulatory elements required for the submandibular gland-specific expression will be delineated using transgenic mice. Within the minimal element, DNA sequences that bind submandibular-gland enriched sequence- specific DNA-binding proteins will be identified by nuclease-protection and by electrophoretic mobility shift assays. To facilitate the identification of tissue-specific regulatory elements, comparisons to regulatory variants of the Mup-1.5a/5b gene will be performed. Following the identification of the cis-acting regulatory elements, the submandibular gland-enriched factor will be cloned in the lambda-gt11 expression vector.